When the China National Tennis Center required an audio upgrade, EZPro stepped up to helm the project. The integrator talks about the challenges it faced and how they were overcome.
China National Tennis Center, built for the 2008 Olympic Games hosted in Beijing, is a symbol of Chinese tennis and a central destination for the game in Asia. Boasting 30 competition courts that provide Grand Slam-level hardware facilities and functional configurations, the venue has been the home of the China Open since 2009.
After more than a decade, the time had come to upgrade the technology at the China National Tennis Center to modernise the experience for all parties. In particular, the venue wanted to address issues with low sound pressure levels, insufficient sound intelligibility, and sound delay. Integrator EZPro was given the responsibility to helm the upgrade project with a focus on four specific areas of the China National Tennis Center.
The Diamond Court is the largest of the China National Tennis Center’s spaces and is used prominently for the China Open. Unsurprisingly, intense attention was paid to it as part of the upgrade works.
The unique configuration of the Diamond Court made it a challenging space to work with. Firstly, the entire space covers 50,000 sqm with 13,520 fixed seats which meant that EZPro had size, stature, and volume to contend with. Secondly, a retractable roof allows the Diamond Court to either be ‘open’ or ‘closed’. The acoustic properties of the space change drastically in either mode of operation, which meant that any proposed audio system had to be able to account for the variable acoustics of the space.
Xiaoyang Wang from EZPro says: “The audio challenges we faced for the Diamond Court were complex. Essentially you have the seated area for the audience and the area on the court from where the presentations happen. Both areas have different audio requirements. And then, due to the retractable roof, we have an additional layer of complexity to solve for. The presenters in the Diamond Court had complained about not being able to hear themselves, due to the reflections of sound in the court. Our solution for this was to build an audio system from the ground up to make sure they had intelligible audio and we even incorporated moveable audio solutions.”
He continues: “For the audience, the original system had been designed by experts that had done a great job already addressing many of the challenges of the Diamond Court. We performed some simulations as well to get a sense of the characteristics of the space and to ensure we get accurate coverage. Our guiding principle was to aim the speakers to project audio at the audience and to have the speakers be as close to the audience as possible. The human body is the best absorber of sound, and we found that with this design choice we could minimise the impact of the retractable roof and provide the audience with the best audio experience possible.”
A total of 40 EAW speakers are used at the Diamond Court. The speakers are arranged in 12 groups with each group comprising three full-range loudspeakers to cover the upper, middle and lower layers of the ‘auditoriums’ at the Diamond Court. The lower auditorium is covered with EAW QX364-WP black point source loudspeakers, which integrate with EAW Focusing, Coaxial Stacking Array (CSA) and other core technologies to provide sound quality and even coverage under high SPL across the distances involved.
The middle and upper auditoriums are respectively covered with EAW MKD1096-WP black and EAW MKD1026-WP black point source loudspeakers. EAW MKD1000 series loudspeakers are also incorporated for their wide horizontal beamwidth which was deemed more suitable for middle distance coverage.
Additionally, four EAW QX364 full-range point source loudspeakers are hung on the four corners of the catwalk to cover the central competition area. Four EAW SB528 woofers are also hung in the court to optimise the LF response. On the first-floor podium, two EAW CPL12M are configured as installed stage monitors and another two EAW CPL12M units used as portable monitors. Allen & Heath dLive C3500 mixer surface + CDM32 MixRack and Allen & Heath Avantis mixer surface + GX4816 MixRack operate as main and backup systems. The audio signals from the main mixer are routed via Dante to the Symetrix Radius NX 4x4 DSP and then feed to Powersoft Quattrocanali series amplifiers. As the backup system, the Allen & Heath Avantis mixer surface + GX4816 MixRack is connected to the Powersoft Quattrocanali series amplifiers via analogue transmission.
The mixers were a crucial part of the upgrade and Wang details: “The mixers provide the option to expand and extend the resources that can be deployed at the China National Tennis Center. The venue is not just used for tennis and sport matches but can host a variety of events and the mixing consoles can be employed to provide support for these activities.”
The upgrade project also encompassed the Lotus Court, Brad Drewett Court, and Moon Court as well as some peripheral outdoor courts. These spaces have been equipped with similar PA systems with a differing range of loudspeakers selected based on the dimensions and requirements of the spaces.
Audio transmission is digital using Dante. But, due to the high requirement for reliability and redundancy, an analogue signal transmission system is also used. The amplifier selection was crucial and Wang talks about the outcome: “The deployment at the China National Tennis Center has been running for close to a year and we have not had any issues with the Powersoft amplifiers due to their robustness and reliability. In addition, Powersoft has a developed management platform that allows us to monitor the amplifiers and provides us with information and data about the state of the equipment. This allows us to stay ahead of any issues and provide support to the client in a prompt and fast manner.”
Helping the team at the China National Tennis Center operate the upgraded systems to maximum potential and maintain them with ease was a specific outcome that EZPro aimed for. To achieve this outcome, a comprehensive control platform has been implemented.
Wang details: “This is a vast deployment, with equipment and technology spread out across all of the China National Tennis Center. Normally at sports venues you will find scattered equipment rooms and difficult to reach installed products which would make the job of operation and maintenance very challenging. But we worked hard to ensure that these challenges would be avoided.”
Wang concludes: “The audio system is managed from a central location and the spaces are equipped with catwalks to ensure that the equipment can be serviced when required. However, due to the size of the venue and the technology deployment it was crucial that we take a proactive approach to management of the systems. The health status and connection of all the equipment can be monitored remotely thanks to the ezCloud intelligent management and control platform. This is something that we have created that integrates all related devices in the AV system through patented multi-protocol network access and distributed encryption interaction technologies. With it, users can employ mobile endpoints such as tablets to conveniently management and control of the entire AV system, getting rid of the constraints of space while reducing operational difficulties.”